2005/01/19 by Susumu Takahashi, Stephen Hill
Chemistry · Materials Science · Physics and Astronomy · #Advanced NMR Techniques and Applications #Magnetism in coordination complexes #Organic and Molecular Conductors Research #cond-mat.other
paper · pdf · doi:10.1063/1.1852859
published as Rev. Sci. Instrum. 76, 023114 (2005) · 11 pages including 8 figures
openalex publication_date 2005/01/19 · arxiv created 2005/05/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The cavity perturbation technique is an extremely powerful method for measuring the electrodynamic response of a material in the millimeter- and submillimeter spectral range (10GHz–1THz), particularly in the case of high-field/frequency magnetic resonance spectroscopy. However, the application of such techniques within the limited space of a high-field magnet presents significant technical challenges. We describe a 7.62mm×7.62mm (diameter×length) rotating cylindrical cavity which overcomes these problems. The cylinder is mounted transverse to the bore of the magnet, coupling is achieved through the sidewalls of the cavity, and the end plate is then rotated (by means of an external drive) instead of the body of the cavity itself. Therefore, rotation does not affect the cylindrical geometry, or the mechanical connections to the incoming waveguides. The TE011 mode frequency of the cavity is 51.863GHz, with the possibility to work on higher-order modes to frequencies of order 350GHz. Neither the quality factor (∼22000 for the fundamental mode) or the coupling to the cavity are significantly affected for full 360° of rotation. The rotation mechanism provides excellent angle resolution (<0.1°), and is compact enough to enable measurements in the high-field (up to 45T) magnets at the National High Magnetic Field Laboratory. Two-axis rotation capabilities are also possible in conjunction with split-pair magnet configurations. We present examples of angle-dependent measurements which illustrate the unique capabilities of this rotating cavity, including: high-field angle-dependent measurements of an unusual form of cyclotron resonance in anisotropic organic conductors; and angle-dependent high-frequency single-crystal electron paramagnetic resonance measurements in single-molecule magnets.